Mechanism for reciprocating grinding wheel spindles



April 18, 1933. w. J. GUILD MECHANISM FOR RECIPROCATING GRINDING WHEEL SPINDLES Filed July 21, 1930 Patented Apr. 18, 1933 UNITED STATES PATENT OFFICE WALDO J. GUILD, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO THE HEALD MA- CHINE COMPANY, OF WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSA- CHUSETTS MECEANISM FOR RECIIROCATING GRINDING WHEEL SPINDLES Application filed July 21, 1930. Serial No. 469,499.

The present invention relates to grinding machines in the operation of which it is desirable to impart a slight reciprocatory motion to the grinding wheel. WVhen grinding work of such width that its entire surface is covered by the wheel, it has been found that a slight reciprocatory motion imparted to the wheel will give a much finer finish t0 the ground surface, as compared to a stationary wheel which tends to form grinding lines on the work.

The object of the present invention is to provide improved mechanism for imparting a slight reciprocatory motion to the spindle of a grinding Wheel, so that the wheel will always give a smooth finish to the work, with no grinding lines. The wheel moving mechanism is automatic in its operation, with a flexibility of control obtained by fluid pressure actuated means, so that the wheel will always grind uniformly to produce a smooth surface. The above and other advantageous features of the invention will hereinafter more fully appear, with reference to the accompanying drawing in which Fig. l is a view in front elevation of a grinding machine embodying the invention.

Fig. 2 is a fragmentary horizontal sectional view along the line 22 of- Fig. 1, looking in the direction of the arrows.

Like reference numerals indicate like parts throughout the drawing.

While the present invention is applicable to grinding machines of various types and of different constructions, it has been illustrated as applied particularly to a machine such as is shown in my co-pending application Serial No. 331,833, filed January 11, 1929, to which reference may be had for details of construction not forming part of this invention. The machine comprises a base 1 having an upright portion 2 upon which is mounted a vertically reciprocable slide 3 providing a workhead 4. Vithin the workhead 4, is mounted a rotatable spindle 5 upon the end of which provision is made for holding a workpiece, means for rotating the spindle 5 being fully shown and described in the aforementioned application. The base 1 also supports an angularly adjustable sub-base 6 which provides ways for the guidance of i not shown, the pulley 11 being mounted upon a shaft 12 carrying at its inner end a gear 13 in mesh with a gear 14. The gear 14 is carried by a shaft 15 which also carries a worm 16 in mesh with a worm gear 17 that is mounted upon a shaft 18 extending at right angles to the shafts l2 and 15. Mounted upon the front end of the shaft 18 are cams 19 and 20, both of which are held on the shaft 18 by means of a nut 21. When the pulley 11 drives the shaft 18 in thedirection of rotation shown by the arrow, it will be seen that the larger cam 19 will cause the vertically reciprocable slide 3 to descend and carry the work downwardly into contact with the grinding wheel 10. It is during the time that the wheel 10 is in contact with the work that it is desirable to reciprocate the wheel, and to this end the smaller cam 20 is provided with a plurality of serrations 22 that are' adapted to control instrumentalities for imparting axial movement to the spindle 9, as will now be described.

Mounted upon the base 1 is a bracket 23 which provides a cylinder 24 having an inlet port 25, an exhaust port 26, and a port 27, connected by a pipe 27a to the wheel spindle moving means. A piston 28 movable in the cylinder 24 provides a reduced portion 29 cooperating with the ports 25,

'26 and 27, and a projecting end portion 30 is connected to a lever 31 pivoted on a pin in which is received one end of a; spring '34, the other end of which abuts the machine frame. a It will be seen that upon rotation of the cam 20 in the direction of the arrow, the serrations 22 will cause the lever 31 to oscillate and this oscillation Will beimparted to piston 28. Fluid under pressure is supplied from any suitable source to the port 25 from which it flows around the reduced portion 29 of the piston 28 to the port 27 and from thence through pipe 27a to the spindle moving means. When the roll 33 drops into a depression 22, the piston 28 is moved toward the left by the spring 34, whereupon the fluid inlet port 25 will be closed and theexhaust port 26 will be opened, thus allowing fluid from the spindle oscillating mechanism to exhaust through the port 26. Thus repeated oscillations of the lever 31 by the serrations 22 on cam 20 will cause fluid pressure to be alternately admitted to and exhausted from cylinder 24.

Mounted upon the wheelhead 8 is a cylinder 35 having a piston 36 movable therein and with an entrance port 37 connected to the port 27 by pipe 27a. The wheelhead 8 also carries a bracket 38 providing a pivot 39 for a bifurcated link 40, the lower end of which provides a reduced portion 41 having an opening 42 for freely receiving a stud 43. The stud 43 is threaded into a boss 44 ,40 check nuts 45 by which the amount of oscillation of the lever 40 can be regulated. In order to impart reciprocatory motion to the wheel spindle 9, a shoulder 9a is provided thereon against which is clamped the inner race of a ball bearing 46 by means of a collar 47 held in place on the spindle by a screw '48, as best shown in Fig. 2. Surrounding the ball bearing 46 is a casing 49 having a cap 50 secured thereto which serves to lock the outer raceway of the ball bearing 46 against a shoulder 49a provided by the casing 49.- The cap 50 provides a flattened portion 51 that is received between the spaced arms of the link 40 and is p'ivotally connected thereto by means of a pin 52. The

- piston 36 projects beyohd the cylinder 35 with its end portion abutting the lower end of the link 40 which is yieldingly maintained against the end of the piston by means of a spring 53. The spring is connected at one end to the link 40 by a pin 54 with its other end connected to a pin 55 carried by the cylinder 35. v 7

With the cam 20 in position shown in Fig; 1, and with inlet port 25 in communication with the port 37 through port 27' and pipe 27a, the pressure fluid exerts its force against the inn r end of the piston 36 and tion of the cam 20 causes the roll 33 to drop into a depression-22, movement of piston 28 will shut off the pressure inlet port 25 and place the exhaust port 26 in communication with port 27. This will allow the fluid in the cylinder 35 to escape through the port 37 and pipe 27a to ports 27 and 26, whereupon the piston 36 will be moved toward the left under the pull of the spring 53. Thus it will be evident that each time the roll 33 drops into one of the depressions 22 on the cam 20, the spindle 9 will be moved to the left,-whereas when roll 33 is lifted out of a depression 22, the spindle will be moved correspondingly to the right, this back and forth movement of the spindle 9 being continued as many times as there are depressions 22 on.

the cam 20. The amount of reciprocatory movement imparted to the spindle 9 is controlled by the setting of the adjustable nuts 45 on the stud 43, the nuts 45 confining the oscillation of the link 40 within the desired limits.

From the foregoing, it is apparent; that by the present invention there is provided an extremely effective mechanism for impart ing a slight reciprocatory movement to a rotating grinding wheel, as it engages the work, so that the ground surface is uniformly smooth and free from grinding lines. The mechanism is very sensitive in its operation, due to the use of a fluid pressure medium for imparting axial movement to the grindin spindle, and the ball bearing con nection etween the spindle and the oscillating lever insures that the spindle will be moved freely, in spite of its high speed of rotation. Obviously, the adjustment of the degree of pivotal movement of the spindle operating lever permits the amplitude of the axial movement of the spindle to be closely set for the work being ground.

I claim,

1. A grinding machine comprising a rotatable grinding wheel spindle mounted for actuate said reciprocating means, and means to procure intermittent operation of said fluid pressure means.

3. In apparatus of the class described, a rotatable grinding wheel spindle, non-rotatable means to reciprocate said spindle, fluid pressure operated means to actuate last named means, and rotatable means to control the actuation of said fluid pressure means.

4/ In apparatus of the class described, the combination with a grinding wheel spindle and a source of fluid pressure, of a cylinder and piston unit to impart reciprocation to said spindle, a valve to control the actuation of said piston from said source, and rotary means to automatically control said valve.

5. In an apparatus of the class described, a rotary grinding wheel spindle, means to reciprocate said spindle, fluid pressure means to actuate said reciprocating means and means to limit the extent of movement of said reciprocating means to vary the reciprocatory stroke of said spindle.

' 6. A grinding machine comprising a rotatable work spindle, a rotatable grinding Wheel spindle, a grinding wheel on said spindle,

means to move the said work spindle relative to said grinding wheel, and means to reciprocate said grinding wheel spindle axially in timed relation to the relative movement between the work spindle and the grinding wheel.

7. A grinding machine comprising a rotatable work spindle, a rotatable grinding wheel spindle, a grinding wheel mounted on said spindle, means for moving said work spindle whereby the workpiece will come into tangential contact with said grinding wheel, and means for reciprocating said wheel during the period of said contact.

8. A grinding machine comprising a rotatable work spindle, a rotatable grinding wheel spindle, a grinding wheel on said wheel spindle, a movable work slide having a rest position and a working position, means to move said work slide from said rest position' through said working position, and means associated with said last named means, in timed relation thereto, whereby said wheel spindle is reciprocated only during the passage of the work spindle through its working position. WALDO J. GUILD. 

